If you are confident you can make the train, then go for it. Personally, that is too tight of a turn for me, so I would spend the first night in Paris, departing early the next morning for Avignon. My understanding is that if you miss the train, you aren't likely to meet a ticket agent who will get you on the next later train for no cost.
I have had apartment rental agents stay late, but have never tried to sweet talk a car rental agent into waiting up for me. Good luck.
Best case scenario, your flight is early, passport control is quick, and you make it to the early train with 20 minutes to spare, so you arrive plenty early enough at Avignon TGV to pick up your rental car.
Worst case scenario (well, not really worst case, but unpleasant), your flight is delayed for 1:15 hrs and passport control is teeming with travelers while half the staff take off for lunch. You miss the TGV, have to repurchase tickets, arrive in Avignon TGV after the car rental agency closes, and you get to look for a hotel in Avignon at 10:30 at night.